STUDY ON MOVEMENT AND DEFORMATION OF GROUND AND SOIL AND ROCK MASS RESULTED FROM EXCAVATION OF TUNNEL WITH CIRCLE SECTION

Tunnel excavation will affect the safety of the surroundings,which induces the displacement and deformation of the above ground. Based on the stochastic medium theory,formulas for predicting the displacement and deformation of the ground and rock mass induced by tunnel excavation are deduced,especially for the tunnels with circle section. Because of the difficulty in the integration,semi-analytical solution of prediction of the displacement and deformation of the above ground is obtained through integrating the horizontal direction and dividing many strips along the depth. Furthermore,a program is developed to compute the movement and deformation of the ground and rock mass resulted from excavation of the tunnel with circle section,which is convenient to be applied in the engineering. Finally,according to the classification of the construction protection, the safety estimation of the influence on the surroundings induced by tunnel excavation is discussed and thecriterion of ground deformation failure is put forward,namely,it is in danger when the ground horizontal deformation is larger than 6 mm/m,otherwise,it is safe. Through an engineering example,the theoretical results and the on-the-spot survey data are consistent,which proves that the computing methods provided are reasonable. The results of the research are significant for tunnel safety construction,and it would be beneficial for the reduction of damage in the constructions and establishments induced by the tunnel excavation.